Share 'Wanted Info - On Ancient Irrigation/Canals Mid/South Americas'

Hi
I believe (not 100% sure) that there was an article in NGM re irrigation etc. Probably in the last 10-20 years.
The article was from a US archeology group, this was their second visit to same site, and described about finds in a valley and the possibilities of sourcing water from adjacent valleys. There were maps outlining the discoveries etc.
Can anyone help me locate this article ? Sor…